Try a split and full elk antler. My girl loves them! And most other things she can A. chew through and eat or B. makes her gums bleed like crazy because the chew is practically indestructible and she has to break it into pieces.
Antlers are the way to go. I would start with split because the marrow is showing and the dogs can really get into that easily and than upgrade to whole antler.
You can get them at pet stores or on amazon!